This invention relates to a control circuit to control at least one lighting device in a vehicle, preferably in a motor vehicle. The invention also relates to a rear view mirror for a vehicle, preferably for a motor vehicle, having such a control circuit installed therein.
In modern day vehicles, lighting devices are not only used for illuminating the street, or for illuminating the passenger cabin, but also in the rear view mirrors. In the prior art, separate control circuits are known to power the separate lighting devices installed in the vehicle. These control circuits are also known as “Light ICs”. For example, a number of different lighting devices could be installed in the rear view mirrors of the vehicle, e.g. for visually indicating a blind spot to the driver, as additional direction indicators, supplementing the direction indicators at the front and rear side of the vehicle, as logo lamp, as puddle light, etc. For all of these different lighting devices, separate control circuits are employed that are each specifically designed for the respective lighting devices. For example, U.S. Pat. No. 5,929,786 A describes a control circuit for blind spot indication. Also, U.S. Pat. No. 6,798,152 B2, GB 2 434 929 A, EP 2 744 302 A1 and U.S. 2012/0086565 A1 relate to control circuits for controlling Light Emitting Diodes, LEDs. EP 2 602 894 A1 relates to a circuit for overload protection.
Therefore, the control circuits that are known in the prior art need to be specifically designed for each specific application. This may lead to a delay in detecting flaws and defects of the control circuits and to a waste of installation room, because several specifically designed control circuits need to be employed. Also, employing specifically designed control circuits prevents the utilization of separately designed developments. Nevertheless, if specifically designed control circuits that have different power demands are to be connected to one single control circuit, the control circuit will most likely be oversized, which leads to a waste of installation space, excessive heat buildup, and high manufacturing costs.
Therefore, it would be desirable to provide a control circuit that is sized so that it can be mounted in components with only limited installation room available, and that can be employed in one single Light IC which can be universally used for various lighting devices having different power requirements.